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LSA question (Cam Guys)

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Old Apr 21, 2007 | 02:53 AM
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Default LSA question (Cam Guys)

I'm getting ready to order a custom cam, and the one that I got a sheet for was set up on a 112lsa. If I changed it to a 111lsa would it screw with valve timing or anything? What effects would it hurt? I know it should bump up DCR just a tad. What else would it do? Thanks
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Old Apr 21, 2007 | 07:41 PM
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Anyone know
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Old Apr 21, 2007 | 07:52 PM
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It will change the valve events. It will give more overlap and slightly more DCR. Plug your cam #s into J-Rod's VE calculator and change the LSA and see how it changes your valve events.
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Old Apr 21, 2007 | 07:59 PM
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I am certainly not a "cam guy"; but I do know that the valve events will change with a resultant increase in overlap and DCR. Whether the effects will be good or bad will depend upon the other specs of the cam in question and how it fits into the total package for your car.
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Old Apr 21, 2007 | 08:52 PM
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Originally Posted by eLTwerker
It will change the valve events. It will give more overlap and slightly more DCR. Plug your cam #s into J-Rod's VE calculator and change the LSA and see how it changes your valve events.
I've tried to download it, but I don't have excell on my laptop.
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Old Apr 21, 2007 | 09:55 PM
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Matt,

When you specified your preferred street manners, you asked for a cam with a light chop, not a heavy lope. Here's what you got:

Camshaft Valve Events: 0.006 0.05 0.2
Intake Duration - ID 280 230 154
Exhaust Duration - ED 279 230 151
Lobe Center Angle - LSA 112 112 112
Intake Centerline - ICL 108 108 108

Intake Valve opens - IVO 32 7 -31 BTDC (- indicates ATDC)
Intake Valve closes - IVC 68 43 5 ABDC
Exhaust Valve Opens - EVO 75.5 51 11.5 BBDC
Exhaust Valve Closes - EVC 23.5 -1 -40.5 ATDC (- indicates BTDC)
Exhaust Centerline - ECL 116 116 116
Overlap 55.5 6 -71.5 degrees
DCR = 7.90:1

Change it to a 111LSA +4, this is what you get:
Camshaft Valve Events: 0.006 0.05 0.2
Intake Duration - ID 280 230 154
Exhaust Duration - ED 279 230 151
Lobe Center Angle - LSA 111 111 111
Intake Centerline - ICL 107 107 107

Intake Valve opens - IVO 33 8 -30 BTDC (- indicates ATDC)
Intake Valve closes - IVC 67 42 4 ABDC
Exhaust Valve Opens - EVO 74.5 50 10.5 BBDC
Exhaust Valve Closes - EVC 24.5 0 -39.5 ATDC (- indicates BTDC)
Exhaust Centerline - ECL 115 115 115
Overlap 57.5 8 -69.5 degrees
DCR = 7.96:1

At a 110LSA +4, this is what you get:
Camshaft Valve Events: 0.006 0.05 0.2
Intake Duration - ID 280 230 154
Exhaust Duration - ED 279 230 151
Lobe Center Angle - LSA 110 110 110
Intake Centerline - ICL 106 106 106

Intake Valve opens - IVO 34 9 -29 BTDC (- indicates ATDC)
Intake Valve closes - IVC 66 41 3 ABDC
Exhaust Valve Opens - EVO 73.5 49 9.5 BBDC
Exhaust Valve Closes - EVC 25.5 1 -38.5 ATDC (- indicates BTDC)
Exhaust Centerline - ECL 114 114 114
Overlap 59.5 10 -67.5 degrees
DCR = 8.02:1
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Old Apr 21, 2007 | 10:38 PM
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Thanks Patrick. I'm going to stick with the 112 lsa you recommended. Thanks again.
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